The disclosed technology relates to a dispersant composition comprising the reaction product of a polyolefin acylating agent and an amine terminated or hydroxyl terminated polyether. In addition, the technology relates to lubricating compositions containing the dispersant composition and an optional synergistic amount of another dispersant, as well as methods of employing the dispersant composition in an engine and engine oils.
Deposit formation resulting from the thermal stressing of engine oil formulations is a growing concern, especially when considering that engines are being designed to be more fuel efficient. Efficiency improving measures are being accomplished, for example, by driving towards smaller sump sizes, turbocharging, and implementing gasoline direct injection (GDI). These efficiency measures impart greater thermal stress to the engine oil formulations used to lubricate the engine. The greater the thermal stress the formulations experience, the increased propensity of the formulation towards deposits, with the net result being loss in engine efficiency and overall life-expectancy.
Additionally, ever-restricting emissions regulations that invariably curb the use of ash-bearing deposit controlling components (because they can irreversibly poison after treatment devices) amplify the formulating challenges to build robust lubricants with low deposit propensity.
Typically, deposits are curbed with high molecular weight polyamine succinimide dispersants of, for example, greater than 20,000 Da. While amine terminated and hydroxyl terminated polyethers can be employed in engine oil formulations to reduce white sludge propensity, the incorporation of such polyethers into dispersant frameworks as a means to reduce the formation of thermally induced deposits, oxidation, and nitration, as well as facilitate TBN retention and seals amelioration has not been considered.
WO 2011/022317, published Feb. 24, 2011 to Barton et al., teaches, among other things, the reaction product of an acid, such as glycolic acid or lactic acid, with an amine, an alcohol, and an aminoalcohol. The low molecular weight, highly polar compositions formed are taught to act as antiwear agents.
A string of publications, including U.S. Pat. No. 7,816,309, issued Oct. 19, 2010, U.S. Pat. No. 7,820,605, issued Oct. 26, 2010, U.S. Pat. No. 7,928,044 issued Apr. 19, 2011 to Stokes et al., and U.S. Pat. No. 7,820,604 issued Oct. 26, 2010, U.S. Pat. No. 7,858,566 issued Dec. 28, 2010, U.S. Pat. No. 8,067,341 issued Nov. 29, 2011 to Ruhe Jr. et al., and U.S. 2009/0270531 published Oct. 29, 2009 to Ruhe, Jr., teach variations of compositions comprised of at least the reaction product of (A) at least one copolymer obtained by free radical copolymerization, and (B) at least one amine terminated ether compound, along with optional further compounds. New dispersant technology is needed.